The Boeing Company has completed integration and test of the U.S. Air Force's first Wideband Global SATCOM (WGS) satellite, bringing its satellite communications services one step closer to the warfighter.
"One WGS satellite will provide more communications capacity than the entire Defense Satellite Communication System constellation that's currently on orbit," said Howard Chambers, vice president and general manager, Boeing Space and Intelligence Systems. "The spacecraft will be a game-changer for the U.S. government and will revolutionize wideband SATCOM capabilities for the warfighter."
According to Boeing the performance of the first WGS satellite during testing "has been excellent," and factory data suggests it will provide approximately 25 percent more communications capacity by the end of its 14-year mission life as a result of high performance margins within the communications payload.
Boeing is under contract for five WGS Block I and II spacecraft, with an option for a sixth. The first satellite has completed factory testing and rigorous mission assurance reviews, and is ready to ship to the launch site in Florida, where it will be launched on a United Launch Alliance Atlas V rocket this August. The spacecraft will be placed into an environmentally-controlled container and transported to Cape Canaveral Air Station in an Air Force C-5 aircraft.
WGS Mission
The Wideband Global SATCOM (WGS) satellites are the key elements of a new high-capacity system that will provide a quantum leap in communications capabilities for the warfighter.
WGS will support the DoD's warfighting information exchange requirements, enabling execution of tactical command and control, communications, and computers; intelligence, surveillance, and reconnaissance (C4ISR); battle management; and combat support information. WGS will also augment the current Ka-band Global Broadcast Service (on UHF F/O satellites) by providing additional information broadcast capabilities.
Each WGS can route 2.1 to 3.6 Gbps of data -- providing more than 10 times the communications capacity of the predecessor DSCS III satellite. Using reconfigurable antennas and a digital channelizer, WGS also offers added flexibility to tailor coverage areas and to connect X-band and Ka-band users anywhere within the satellite field of view. The system provides tremendous operational flexibility and delivers the needed capacity, coverage, connectivity and control in support of demanding operational scenarios.
Boeing was awarded the WGS initial contract in January 2001 for the first three satellites plus the associated ground-based command and control elements. Integrated logistics, training, and sustaining engineering support are also provided by Boeing. The procuring agency is the U.S. Air Force Space Command's MILSATCOM Systems Wing at Los Angeles AFB, California.
The WGS space segment will initially consist of three geostationary satellites operating over Pacific, Indian and Atlantic regions. Under a Block II contract, a fourth and fifth satellite are being procured to meet the warfighter's evolving SATCOM bandwidth requirements. The Block II satellites will be similar to the three Block I satellites already in production and will add a radio frequency bypass capability designed to support airborne intelligence, surveillance and reconnaissance platforms requiring ultra-high bandwidth and data rates demanded by unmanned aerial vehicles.
The first Wideband Global SATCOM satellite is scheduled for launch in Mid 2007 aboard an Atlas V Launch Vehicle. WGS will provide transformational capabilities supporting government objectives for the Transformational Communications Architecture in the next decade and beyond.
Boeing was awarded the WGS initial contract in January 2001 for the first three satellites plus the associated ground-based command and control elements. Integrated logistics, training, and sustaining engineering support are also provided by Boeing. In 2006, Boeing was authorized to produce two additional WGS satellites. The procuring agency is the U.S. Air Force Space Command's MILSATCOM Systems Wing at Los Angeles AFB, California.
With an initial launch scheduled in 2007, WGS will provide transformational capabilities supporting government objectives for the Transformational Communications Architecture in the next decade and beyond.
Capacity:
WGS supports communications links within the Government's allocated 500 MHz of X-band and 1 GHz of Ka-band spectrum. The WGS payload can filter and route 4.875 GHz of instantaneous bandwidth. Depending on the mix of ground terminals, data rates and modulation schemes employed, each satellite can support data transmission rates ranging from 2.1 Gbps to more than 3.6 Gbps. By comparison, a DSCS III satellite will support up to 0.25 Gbps.
Coverage:
The WGS design includes 19 independent coverage areas that can be positioned throughout the field of view of each satellite. This includes eight steerable and shapeable X-band beams formed by separate transmit and receive phased arrays; 10 Ka-band beams served by independently steerable, diplexed antennas, including three with selectable RF polarization; and transmit/receive X-band Earth coverage beams.
Connectivity:
The enhanced connectivity capabilities of WGS enable any user to communicate with any other user with very efficient use of satellite bandwidth. A digital channelizer divides the uplink bandwidth into nearly 1,900 independently routable 2.6 MHz subchannels, providing connectivity from any uplink coverage area to any downlink coverage area (including the ability to cross-band between X and Ka frequencies). In addition, the channelizer supports multicast and broadcast services and provides an effective and flexible uplink spectrum monitoring capability to support network control.
The figure below shows how the X-band and Ka-band antenna suites are interconnected via the digital channelizer to provide the unique flexibility and connectivity of WGS.
Command and Control: Control of the WGS communications payloads is accomplished from four Army Wideband Satellite Operations Centers (WSOCs), using ground equipment hardware and software developed by Boeing, ITT Industries, and Raytheon Corp. Each Global Satellite Configuration and Control Element (GSCCE) has the capability to control up to three satellites at a time, via "in-band" (X-band or Ka-band) telemetry and command links. Spacecraft platform control is accomplished by the 3rd Space Operations Squadron (3 SOPS) at Schriever AFB in Colorado Springs, using WGS mission unique software and databases provided by Boeing, hosted on the Command and Control Segment Consolidated (CCS-C) systems that are being fielded by Integral Systems, Inc. The satellite is designed for compatibility with the current S-band SGLS TT&C capability, as well as the planned Unified S-band (USB) formats and frequencies.
Boeing 702 Platform :
The Boeing 702 satellite is the industry leader in capacity, performance and cost-efficiency. Enabling technologies for the advanced 702 design are the xenon-ion propulsion system (XIPS), highly efficient triple-junction gallium arsenide solar cells, and deployable radiators with flexible heat pipes.
XIPS is 10 times more efficient than conventional bipropellant systems. Four 25-cm thrusters remove orbit eccentricity during transfer orbit operations and are used for orbit maintenance and to perform station change maneuvers as required throughout the mission life. Deployable radiators with flexible heat pipes provide substantially more radiator area, resulting in a cooler, more stable thermal environment for both bus and payload. This increases component reliability and reduces performance variations over life.
Summary
As the leading provider of advanced satellite communications systems for broadcast and packet-switched satellite communications, Boeing has leveraged a wealth of Government and commercial experience and technology for WGS. This includes the company's extensive investments to develop the Boeing 702, as well as prior work on phased array antennas and digital signal processors. Together these technologies enabled the tremendous capacity and operational flexibility sought for the WGS space segment. Additionally, these core capabilities can support WGS evolution to satisfy additional transformational requirements of the warfighter, such as improved connectivity for intelligence, surveillance and reconnaissance platforms and network-centric communications architectures.
